The structure of a DnaA/HobA complex from Helicobacter pylori provides insight into regulation of DNA replication in bacteria
- 15 December 2009
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 106 (50), 21115-21120
- https://doi.org/10.1073/pnas.0908966106
Abstract
Bacterial DNA replication requires DnaA, an AAA+ ATPase that initiates replication at a specific chromosome region, oriC, and is regulated by species-specific regulators that directly bind DnaA. HobA is a DnaA binding protein, recently identified as an essential regulator of DNA replication in Helicobacter pylori. We report the crystal structure of HobA in complex with domains I and II of DnaA (DnaAI–II) from H. pylori, the first structure of DnaA bound to one of its regulators. Biochemical characterization of the complex formed shows that a tetramer of HobA binds four DnaAI–II molecules, and that DnaAI–II is unable to oligomerize by itself. Mutagenesis and protein–protein interaction studies demonstrate that some of the residues located at the HobA-DnaAI–II interface in the structure are necessary for complex formation. Introduction of selected mutations into H. pylori shows that the disruption of the interaction between HobA and DnaA is lethal for the bacteria. Remarkably, the DnaA binding site of HobA is conserved in DiaA from Escherichia coli, suggesting that the structure of the HobA/DnaA complex represents a model for DnaA regulation in other Gram-negative bacteria. Our data, together with those from other studies, indicate that HobA could play a crucial scaffolding role during the initiation of replication in H. pylori by organizing the first step of DnaA oligomerization and attachment to oriC.Keywords
This publication has 39 references indexed in Scilit:
- DiaA, a Novel DnaA-binding Protein, Ensures the Timely Initiation of Escherichia coli Chromosome ReplicationPublished by Elsevier BV ,2004
- Biochemical Characterization of Protein Complexes from the Helicobacter pylori Protein Interaction MapMolecular & Cellular Proteomics, 2004
- DnaA Protein of Escherichia coli: oligomerization at the E. coli chromosomal origin is required for initiation and involves specific N‐terminal amino acidsMolecular Microbiology, 2003
- Structural basis of replication origin recognition by the DnaA proteinNucleic Acids Research, 2003
- The structure of bacterial DnaA: implications for general mechanisms underlying DNA replication initiationThe EMBO Journal, 2002
- Identification of a putative chromosomal replication origin from Helicobacter pylori and its interaction with the initiator protein DnaANucleic Acids Research, 2001
- The protein–protein interaction map of Helicobacter pyloriNature, 2001
- Escherichia coli DnaA ProteinPublished by Elsevier BV ,1998
- The complete genome sequence of the gastric pathogen Helicobacter pyloriNature, 1997
- Replication initiated at the origin (oriC) of the E. coli chromosome reconstituted with purified enzymesCell, 1984